The Camera Axe is a tool for photographers to trigger cameras or flashes based on signals from various sensors. In this version there are two ports for sensors such as a microphone, a motion detector, or light sensor; and there are two ports for camera/flash devices. The Camera Axe is useful for stop motion photography where an action happens too quickly for human reflexes (photographing a popping balloon, lightning, or a milk droplet splash). Other uses can be to catch things photographers don't want to wait around for such as birds flying to a bird feeder or surveillance of people walking down a hallway. The possibilities are endless. The hardware and firmware for this device are all open source under Creative Commons Attribution 3.0 License (Creative Commons — Attribution 3.0 Unported — CC BY 3.0) meaning that it's possible to adapt this platform for specialized uses.
While it is a custom circuit board it uses arduino software. Visit my blog for more details: Hobby Robotics » Camera Axe 3.0
Here are a few example pictures I took: